import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N = I()
C,V = MI()

inf = 10**18
dp = [inf]*(2*N+1)
dp[1] = 0
for i in range(1,N+1):
    for j in range(2*i,2*N+1,i):
        dp[j] = min(dp[j],dp[i]+C+V*(j//i-1))

ans = min(dp[i] for i in range(N,2*N+1))
print(ans)